hiv vACCinE FEAt lEAvEs morE quEstions thAnAnswErs
only hours AFtEr hiv vACCinE rEsEArChErs AnnounCED thE AChiEvEmEnt oF A milEstonE thAt hAs EluDED thEm For A quArtEr oF A CEntury, thEy BEgAn plotting thEir nExt stEps—AnD Coming BACk to rEAlity. thEir ultimAtE goAl, hAlting thE sprEAD oFAiDs, rEmAins FAr in thE FuturE.A、thAi AnDAmEriCAn tEAm hAD AnnounCED EArly thursDAy inBAngkok thAt thEy hAD FounD A ComBinAtion oF vACCinEs thAt proviDED moDEst protECtion AgAinst inFECtion with hiv, oFFEring thE First prooF oF prinCiplE thAt thE DEADly DisEAsE CoulD BE tAmED By tEAChing thE immunE systEm to rECognizE thE virus AnD DEFEAt it. sCiEntists ArounD thE worlD hAilED thE AChiEvEmEnt.
But By thursDAy AFtErnoon, thE initiAl wAvE oF joy hAD givEn wAy to thE rECognition thAt mAny quEstions will hAvE to BE AnswErED BEForE rEsEArChErs CAn proDuCE A vACCinE thAt will rEliABly shiElD pEoplE From hiv. For stArtErs, it CoulD tAkE yEArs to FigurE out thE BiologiCAl mEChAnisms thAt proDuCED thE AppArEnt 31% rEDuCtion in inFECtions Among thosE givEn thE vACCinE trEAtmEnt.
rEsEArChErs hAvE nEvEr BEForE oBsErvED AntiBoDiEs(抗体) or othEr molECulEs in thE BlooD thAt CoulD BloCk An inFECtion oF hiv, thE virus thAt CAusEsAiDs. now thEy will try to FigurE out whEthEr this ComBinAtion oF vACCinEs stimulAtED nEw molECulEs, or provokED An unusuAl BlEnD oF onEs prEviously oBsErvED、ExpErts prEDiCtED thAt it woulD rEquirE 2 to 3 yEArs oF rEsEArCh to BEttEr unDErstAnD how thE vACCinE workED, AnD An ADDitionAl 5 to 10 yEArs to proDuCE A vACCinE thAt wAs rEADy to tEst in pEoplE. somE rEsEArChErs EvEn wonDErED whEthEr thE AppArEnt rEDuCtion in inFECtions wAs simply A stAtistiCAl mistAkE rEsulting From thE smAll numBEr oF hiv CAsEs oBsErvED in thE triAl.
thE ABunDAnCE oF unAnswErED quEstions hAsn’t sAppED thE EnthusiAsm oF mAny hiv rEsEArChErs.AFtEr 26 yEArs oF sEEmingly FutilE rEsEArCh on vACCinEs, thEy hAvE FinAlly mADE somE progrEss on DEmonstrAting thE FEAsiBility oF An hiv vACCinE, sAiDDr.Anthony FAuCi, DirECtor oF thE nAtionAl institutE oFAllErgy AnD inFECtiousDisEAsEs, whiCh lArgEly FunDED thE $120-million stuDy. "this is thE First positivE signAl—moDEst though it mAy BE—thAt wE hAvE EvEr got with Any vACCinE thAt wE hAvE EvEr tEstED in humAns," FAuCi sAiD、But "is it A vACCinE thAt is rEADy For primE timE no."
thE thAi triAl, whiCh BEgAn in 2003, hAD BEEn lAughED At By mAny CritiCs As A wAstE oF timE AnD monEy BECAusE its two vACCinEs hAD proDuCED no BEnEFit in inDiviDuAl triAls.But A FEw rEsEArChErs spECulAtED thAt using thEm togEthEr—with onE vACCinE priming (开始修复) thE immunE systEm AnD thE sEConD Boosting thAt rEsponsE woulD BE morE EFFECtivE. thE primEr in this ComBinAtion isAlvAC, mADE By sAnoFi pAstEur, whiCh usEs A hArmlEss virus to CArry thrEE synthEtiC hiv gEnEs into thE BoDy. thE Boost ComEs FromAiDsvAx, originAlly mADE By vAxgEn inC、AnD now ownED By thE nonproFit group gloBAl solutions For inFECtiousDisEAsEs. it ContAins A gEnEtiCAlly EnginEErED vErsion oF A protEin From thE hiv surFACE.
thE stuDy, lED ByDr. supAChAi rErks-ngArm oF thE thAi ministry oF puBliC hEAlth’sDEpArtmEnt oFDisEAsEControl, involvED morE thAn 16,000 voluntEErs in thAilAnD, All From thE gEnErAl populAtion rAthEr thAn From A pool oF high-risk homosExuAls AnD Drug usErs usED in pAst stuDiEs. hAlF rECEivED Four priming DosEs oFAlvAC AnD two Boost DosEs oFAiDsvAx ovEr A six-month pErioD; thE othEr hAlF rECEivED plACEBo(无效对照药) shots.AFtEr thrEE yEArs oF Follow-up, nEw hiv inFECtions wErE oBsErvED in 74 oF thE 8,198 pEoplE who rECEivED thE plACEBo, But in only 51 oF thE 8,197 givEn thE vACCinE, A stAtistiCAlly signiFiCAnt 31% rEDuCtion.
to thE rEsEArChErs’ DisAppointmEnt, howEvEr, thE vACCinE DiD not rEDuCE lEvEls oF hiv ACtivity in thosE who BECAmE inFECtED AFtEr BEing vACCinAtED、thE triAl wAs CArriED out in thAilAnD BECAusE thE initiAl rEsEArCh wAs ConDuCtED thErE AnD thE v